1. Field of the Invention
The present invention relates to a sensor for measuring in particular physical variables and for passing on the measured variable through an interface (in particular an output) as a sensor signal to an electrical device, in particular a control device. The invention also relates to a circuit having at least two sensors, including a sensor of the type mentioned at the outset, a method for operating a sensor of the type mentioned at the outset and a method for operating the circuit including at least two sensors.
A sensor of the type mentioned at the outset has a converter element which converts the variable into an electrical signal. In addition, the sensor includes an electronic evaluation circuit, for example in the form of a signal processing unit, for the purpose of conditioning and/or processing the electrical signal to provide the sensor signal. In that case, the electronic circuit has a device for diagnosis (diagnosis device).
In the case of the sensors known from the prior art, the diagnosis device monitors the various functions of the sensor. When a fault occurs, the end stage of the sensor is typically switched off in such a way that there is no longer a sensor signal present at the output of the sensor.
The disadvantage of such a sensor in which the sensor is switched off in the event of a fault is the fact that the electrical device to which the sensor is connected cannot distinguish whether failure of the sensor has been brought about by a fault in the sensor or by a fault in the line connection between the sensor and the electrical device. This means that it is necessary for an operator to first have to analyze which type of fault is present before corrective maintenance can be carried out. This is often time-consuming and, because trial-and-error methods are often used to find the fault, leads to unnecessary assembly operations.